The present invention relates generally to remote sensing and in particular, it provides a system and method of sensing parameters in a controlled mobile environment or other mobile applications over long distances via a satellite communication link.
When perishable goods such as fruits, vegetables, fish meat or dairy products are shipped, it is necessary to load them into a controlled environment for the journey. This is particularly the case for delivery over long distances, such as by ship, train or road transport, where goods are transported in shipping containers, as it is necessary to maintain at least the temperature of the goods within acceptable limits over the duration of the journey. In some instances, humidity and various other gas concentrations must also be maintained within specified limits in order to guarantee safe delivery of the goods.
In the past, refrigerated shipping containers were set up with temperature recording apparatus for measuring internal temperature (and also humidity where applicable), at a point external to the container, such that an engineer could periodically monitor the temperature inside each container and act where necessary to maintain the refrigeration equipment to ensure safe passage of the goods. Unfortunately, it has often been observed, at the end of such a journey, that goods in a container have spoiled because the external display has not accurately reflected the internal conditions in the containers. This in turn, leads to expenses for the insurer, the disappointment of the recipient, who does not have the benefit of the product being delivered and often, damage to the business and the reputation of the supplier when the recipient resorts to other, more reliable markets.
According to a first aspect, the present invention consists in a telemetry system for measuring one or more parameters and transmitting a signal representing the value or values of the one or more measured parameters over a significant distance via at least one communication network the system comprising parameter measurement means to measure the respective parameters, signal generator means to generate a signal representative of the measured value for transmission and local communication means for transmitting the signal via the at least one communication network to a receiving station connected to the communications network and monitoring means also connected to the communications network for receiving the signal and indicating if the value or any one of the values represented by the signal.
According to a second aspect, the invention provides a remote sensing unit for a telemetry system, the remote sensing unit comprising:
parameter measurement means to measure a parameter or parameters of interest;
signal generator means to generate a signal representative of the measured value of the or each parameter; and
communication means for transmitting the signal to a transceiver, located on the ship or vehicle when the ship or vehicle is in transit for further transmission via a communication network.
According to a third aspect, the invention provides a control unit arranged to be connectable to a data logging device and including trigger signal generating means to trigger the data logger to download data, data input means to receive data from a connected data logger, signal generating means to generate a signal encoding the downloaded data in a format suitable for transmission over a communications network and input/output means arranged for connection to a communications device for communicating the signal generated by the signal generating means to the communication device.
The transceiver may be a transponder, arranged only to transmit on an interrogation from the satellite, or may be a transceiver arranged to initiate communication with a satellite mounted transponder.
The transceiver may also be an interface to a land based telecommunications network such as a public switched telephone network.
The system of the present invention is particularly useful for monitoring conditions within a standard shipping container of the type typically used in sea transportation, however, it is equally applicable for use in other types of containers and in fact, in fixed shipboard or vehicle mounted locations such as an equipment space where bilge pumping equipment might be located. By enabling communication with any network to which a suitable interface is provided, a container may be monitored while on land vehicles, in storage awaiting trans-shipment and on sea-going vessels.
In one particular embodiment, a plurality of containers are fitted with monitoring systems and each transmits information as required, to others of the containers similarly fitted with monitoring devices. One of the containers is then fitted with a master transceiver for receiving signals from the monitoring systems of other containers such that the master transceiver may collect and transmit all of the signals from all of the other monitoring systems to the satellite, either directly or via an intermediate transceiver or transponder mounted elsewhere in the ship or other vehicle.
In a further variation, the monitoring systems, or at least some of the monitoring systems located in the containers are interconnected to one another by wire connections. Similarly, the master transceiver and possibly also the main transceiver for satellite communication may also connect to the other monitoring systems by cable, such that the only reliance on wireless communication is between the satellite and the main transceiver, and between the satellite and the earth station.
In an extended embodiment of the invention, the monitoring functions of the remote sensing unit may include, as well as inputs for monitoring temperature and humidity, inputs for monitoring air flow, air pressure (or partial pressure of components), location (via GPS), shock, voltage, current (power supply conditions of environmental control equipment or other equipment supporting or forming part of the consignment), shaft speed (RPM), water purity, filtration operation, illumination levels, pollution levels (eg; engine emissions), security breaches (opening of doors/windows or interruption of security beams or other security devices), surveillance camera operation or motion detection.
As well as the monitoring of perishable food items such as produce, dairy, seafood, meat, wine and flowers etc, other applications for embodiments of the present invention, include the monitoring of hazardous cargoes such as, oil, other flammable or toxic goods, cotton, coal etc, environmental hazards or equipment for minimising hazards, such as, pollution controls, machinery discharge, sewage outflows, discharge of ships"" ballast, monitoring of pollution factors such as noise, air quality, water quality or the monitoring of security such as by monitoring position (eg; GPS), surveillance cameras, locking and unlocking of controlled spaces, entry and exit of controlled spaces, or any other compatible monitoring or security functions.
Therefore, for example, a ship could be monitored for opening of its ballast valves and the location reported back to a central site. This process might also monitor the duration and volume of the dump.
It would also be possible to monitor complex sets of environmental parameters such as ethylene concentration, oxygen and humidity in the atmosphere inside a container as well as temperature and to use these parameters to predict a projected state of a perishable cargo, such as fruit at the end of a journey, from a history of the conditions to which the cargo has been subjected up to the current point in the journey.
In a first embodiment, the measurement of the one or more parameter values is performed by a stand alone data logging device which includes measurement means for measuring the parameter values, which might typically be temperature and humidity, storage means such as a digital memory or a magnetic storage device such as a floppy disk drive to record the measured parameter values and control means to periodically cause the measurement to be made and recorded in the storage means. The control means also preferably includes an input/output means for receiving a trigger signal to trigger the down loading of data and in response to the trigger signal, generating an output signal representing some or all of the data held in the storage means. Preferably, the control means records the parameter values at regular intervals for example, in the range of once per 10 minutes to once per 2 hours.
In the first embodiment, a control unit is connected to the data logger and to the transmission means and for transmission via the at least one transceiver. The control unit can either be arranged to periodically download the data from the data logger and initiate a transmission automatically, or alternatively, the control unit may be arranged to respond to a signal transmitted to the communication means from the monitoring means via the at least one transceiver to then unload data from the data logger and transmit it to the receiving station. In the case where the control unit periodically initiates downloading of data for transmission without prompting from the monitoring means, the control unit may also examine the data and if it is in tolerance, it may merely send a transmission indicating that the system is operating correctly and all data is in tolerance rather than sending all of the recorded data.
Preferably, the communication means is a transmitter arranged to transmit to a local transceiver which in turn relays the signal to the receiving station via pre-existing communications channels. In the case of shipboard operation, the pre-existing communications system may include a communications channel associated with a satellite navigation system, which in turn communicates with a private or public switched network. The communication means in this case, a low power transmitter which communicates with a shipboard transceiver, which in turn signals via a satellite to a ground station where interconnection with the switched network occurs.